To Remove Dead Leaves or Not

It all started when an article called “Leaf It Be!” was distributed via email list to gardeners in my area (around Metro DC). In it, the author comes to the rescue of dead leaves, saying they’re ”an important part of the ecosystem, a natural fertilizer. When did they become our enemy?” And she’s right – dead leaves, when left in the garden, hold water, neutralize acid, and slowly release nutrients. They’re a valuable resource that we can all agree doesn’t belong in some landfill.

But figuring out exactly WHAT to do with dead leaves turns out to be no easy thing. ‘Leaf it Be!” and a bunch of animated email group responses to it got me interested in the answer(s).

In Borders and around Trees and Shrubs

More and more, we’re being urged to leave dead leaves in place in the garden, and clearly in some situations it’s a fine idea. But not for all, including my own garden with its abundance of mature oaks. Like most everything in nature, it depends. In this case, you have to ask:

How many leaves are we talking about?

How kind of leaves – the big oak leaves that prevent water from penetrating the soil, or thin elm leaves that don’t smother plants?

And will the leaves be covering a groundcover you’d rather not kill?

What everyone DOES agree on is that putting chopped dead leaves in borders and around trees and shrubs is fine. Actually, it’s terrific – because chopped leaves do all those great things that leaves do, without doing any harm. They have all the benefits we’ve come to know and love in any good organic mulch, which is what chopped leaves become. For more about chopped-leaf mulch, check the Illinois Extension Service.

On Lawn

Apparently NO one is suggesting that whole leaves be allowed to sit on and eventually smother the lawn. (Here’s a good article on the subject) But it’s also true that lots of experts are now advising chopping up the leaves that drop on lawn - by mowing over them – and leaving them in place to serve as a source of organic matter for the soil and some nutrients for the turfgrass. Chopped leaves are known to increase microbial activity in the soil.

But wait; there’s more. Some brand-new research proves that chopped leaves not only add organic matter and nutrients – they suppress weeds! Here’s the story.

Anywhere in the Garden

With all this discussion of leaves being left in the garden, an email from Ed Brandt to the email group got everyone’s attention because he’s a big shot in the regional office of the EPA. He quoted from the Tick Management Handbook by Kirby Stafford, which repeatedly recommends removing leaves. It wasn’t clear if that included chopped leaves, so we need a bit of clarification there, Ed.

On Hard Surfaces

For obvious safety purposes, dead leaves should be removed early and often from surfaces people walk on. And certainly all wood surfaces benefit from having the leaves removed to prevent rotting.